turbocharged cb550 bobber

Slow progress is still progress right? I ended up struggling with my steel intake manifold quite a bit. Wouldn't seal up to the head that well, and there were quite a few vacuum leaks in the welds that I was having trouble sealing up. Now we're gonna try this aluminum plenum style intake. Hoping this ends up working well with a little bit of boost. Made it using the factory intake runners so I have the nice O ring grooves to seal it to the head. I cut the pieces and had a local shop tig weld it up for me.
 

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Really interesting build man. I really want you to figure all the turbo kinks out. Hopefully this plenum version will help
 
no he just has not drilled the plenum for the direct injection setup yet
 
Sonreir said:
We probably covered this already, but you're doing a draw-through setup, right?

Yes, the current plan is to see how this thing performs on it. its a 38mm cv carb with an accelerator pump from a harley
 

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mswans said:
Yes, the current plan is to see how this thing performs on it. its a 38mm cv carb with an accelerator pump from a harley
Hopefully better than my round slide worked. One of these days I'll finish that bike.


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Well i made a little winter progress on the bike. Aluminum plenum intake is what i should have done off the get go. Bike starts and idles well. think I've got the pilot circuit close to fine tuned on this 38mm cv carb. Waiting on warmer weather to see how the main jet does down the highway. Just a couple small things left to do before this bike is ready to hit the road. Waiting on winter temps to get a little warmer here in iowa before I can do that!
 

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Wow, that was a good amount of work. Hopefully the Canadian air will move back up there for a bit. Hard to test and tune when the high is still below freezing. Good stuff! 8) 8) 8)
 
Made a fairly successful maiden voyage. Put 22 miles on it. Scary power for the size of this bike. Saw boost get up around 13-14 psi a few times, thats a lot more than I wanted but it looks like the motor took it fairly well. It is leaking oil around the MLS head gasket pretty good. Hoping that re torquing the A.P.E. cylinder studs slows this down. Also needs geared lower, previous owner must have been trying to set some land speed records.
 
With regards to the boost-level: At 14PSI I seriously hope your gauge is misreading. Also you may want to check oil-flow to the turbo, at least take off the return line just to make sure you have good flow.
 
der_nanno said:
With regards to the boost-level: At 14PSI I seriously hope your gauge is misreading. Also you may want to check oil-flow to the turbo, at least take off the return line just to make sure you have good flow.
Thats something to consider, I could check the gauge against another air pressure gauge. Its a brand new sun pro. I didn't see any of the crazy boost until the tach was way up above 10k. May have even seen 12k a couple times, makes me question the accuracy of the tach.

Hard to say exactly where all the numbers were, but it stayed at a pretty steady 5lbs in the 6k-10k rpm range. I didn't mean to push the limits this far on the poor thing, I had done it a few times before I took the time to actually pay attention to the gauges during acceleration.

I'm sure if the turbo was not getting oil it would be long cooked by now. I can pull off the drain line and eyeball the flow, just might be tricky to eyeball how much oil should be going through a journal bearing turbo.
 
How is the throttle response with the draw through setup?
Did you use any carbon seals on the turbo?
I originally planned to draw through my XS shitheap project,and decided to blow through due to hearsay about drivability improvements, although fuel pump, pressure regulator and etc are proving to be a pain in the ass
Bike sounds wicked
 
If you don't have mad power-goals and choose a sufficiently small turbo, response won't be too bad. Even on my TR1 with the oversized T3, it responded a bit more sluggish than a n/a bike.
 
rusche said:
How is the throttle response with the draw through setup?
Did you use any carbon seals on the turbo?
I originally planned to draw through my XS shitheap project,and decided to blow through due to hearsay about drivability improvements, although fuel pump, pressure regulator and etc are proving to be a pain in the ass
Bike sounds wicked

Throttle response is not bad at all. Theres a bit of hesitation just above idle, but after that its a screamer. And no carbon seals, just the regular piston ring type.
 
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